A5062498976- Carbohydrate Chemistry and Synthesis
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Glycosylation and Glycoproteins Research
- Protein Tyrosine Phosphatases
- Phytochemicals and Medicinal Plants
- Protein Kinase Regulation and GTPase Signaling
- Chemical Synthesis and Analysis
- Synthetic Organic Chemistry Methods
- Bioactive Compounds and Antitumor Agents
- Microbial Natural Products and Biosynthesis
- Radical Photochemical Reactions
- Ubiquitin and proteasome pathways
- Fluorine in Organic Chemistry
- Click Chemistry and Applications
- Biochemical and Molecular Research
- Oxidative Organic Chemistry Reactions
- Marine Sponges and Natural Products
- Receptor Mechanisms and Signaling
- Catalytic C–H Functionalization Methods
- Crystallography and molecular interactions
- Galectins and Cancer Biology
- Sulfur-Based Synthesis Techniques
- Plant biochemistry and biosynthesis
- Asymmetric Synthesis and Catalysis
Kyushu University
2016-2024
RIKEN Center for Sustainable Resource Science
2014-2024
RIKEN
2008-2022
Pioneer (Japan)
2019-2022
Fukuoka University
2020
RIKEN Advanced Science Institute
2008-2018
State Key Laboratory of Synthetic Chemistry
2006-2016
Centre de Recherche en Économie et Statistique
2015-2016
Centre for Research in Engineering Surface Technology
2015-2016
Center for Responsible Travel
2015-2016
The acetal (O-glycoside) bonds of glycans and glycoconjugates are chemically biologically vulnerable, therefore C-glycosides interest as more stable analogs. We hypothesized that, if the O-glycoside linkage plays a vital role in glycan function, biological activities C-glycoside analogs would vary depending on their substituents. Based this idea, we adopted "linkage-editing strategy" for creation (pseudo-glycans). designed three types pseudo-glycans with CH2 CHF linkages, which resemble...
Oseltamivir (Tamiflu) and zanamivir (Relenza), two extensively used clinically effective anti-influenza drugs, are viral sialidase (also known as neuraminidase) inhibitors that prevent the release of progeny virions thereby limit spread infection. Recently mortalities neuropsychiatric events have been reported with use oseltamivir, especially in pediatric cases Japan, suggesting these drugs might also inhibit endogenous enzymes involved sialic acid metabolism, including sialidase,...
C-Glycoside analogs of naturally occurring glycoconjugates are useful tools for chemical biology studies, but their synthesis usually requires protection the hydroxyl groups glycosyl donors. Here we report protecting-group-free and photoredox-catalyzed C-glycosylation with sulfinates Michael acceptors via Giese radical addition.
C-Glycosides are metabolically stable mimics of natural O-glycosides and expected to be useful tools for investigation the biological functions glycans. Here, we describe synthesis a series aryl vinyl C-glycosides by stereoinvertive sp3–sp2 cross-coupling reactions 2-deoxyglycosyl boronic acid derivatives with or halide, mediated photoredox/nickel dual catalytic system. Hydrogenation afforded C-linked 2′-deoxydisaccharide analogues.
Abstract A series of novel optically active [5]helicene-derived phosphine ligands ( L1 , with a 7,8-dihydro[5]helicene core structure- and L2 fully aromatic [5]helicene structure) were synthesized. Despite their structural similarities, exhibit particularly different characteristics in use as chiral ligands. was highly effective the asymmetric allylation indoles 1,3-diphenylallyl acetate (up to 99% ee), etherification alcohols 96% ee). In contrast, stereocontrol helical chirality...
Sialidase-resistant ganglioside analogues having biological activities similar to those of natural gangliosides are expected be important probes for clarifying the functions gangliosides. Focusing on difluoromethylene-linked (CF2-linked) α(2,3)sialylgalactose as a core structure sialidase-resistant mimics, we have developed novel, stereocontrolled, and efficient methodologies synthesize CF2-sialosides based Ireland−Claisen rearrangement. CF2-linked GM4 were synthesized.
Abstract π‐Conjugated helicenes containing heteroatoms have attracted significant attention due to their diverse chemical and electronic structures, as well tunable physical properties. It was rationally anticipated that the self‐assembly of coumarin‐fused would be controlled by effects a substituent on internal edge helix. Here, this work reports efficient syntheses 1 , b (R=Ph, Me), enantioselective synthesis (R=Ph) chiral Au I ‐catalyzed hydroarylation. The helical structure unambiguously...
C-Linked carbohydrate structure, in which the cleavable O-glycosidic linkage is replaced by a carbon unit, useful tool for functional analyses of glycoconjugates. We describe synthetic method α-CH2-linked disaccharide structures, such as Glc(1,6)-Glc, stereoselective radical-coupling C-glycosylation between conformationally constrained and stable C1-sp3 hybridized xanthate donor carefully designed acceptor.
We describe a new synthetic approach for C-linked glycolipid analogues, in which the cleavable O-glycosidic linkage is replaced by carbon unit. Direct C-glycosylation of conformationally constrained and stable C1-sp3 hybridized xanthate carbohydrate with carefully designed sphingosine units afforded CH2-linked analogue antitumor-active KRN7000 its glucose congener.
The genus Physalis in the Solanaceae family contains several species of benefit to humans. Examples include alkekengi (Chinese-lantern plant, hōzuki Japanese) used for medicinal and decorative purposes, peruviana, also known as Cape gooseberry, which bears an edible, vitamin-rich fruit. Members are a valuable resource phytochemicals needed development medicines functional foods. To fully utilize potential these we need understand their biosynthesis, this genomic data, especially...
Abstract We have developed radical C‐glycosylation using photoexcitable unprotected glycosyl borate. The direct excitation of borate under visible light irradiation enabled the generation anomeric without any photoredox catalysts. in situ generated was applicable to addition such as Giese‐type and Minisci‐type reaction introduce alkyl heteroaryl groups at position. In addition, radical–radical coupling between acyl imidazolide provided C‐glycosides.
The biomimetic synthesis of the advanced model compound chloropupukeananin has been achieved. present features an unexpected enantiomer-differentiating Diels–Alder/carbonyl-ene cascade under high-pressure conditions and a base-promoted migration salicyl group.
Photoaffinity labeling (PAL) is an important tool in chemical biology research, but application of α-ketoamides for PAL has been hampered by their photoinstability. Here, we show that 2-thienyl-substituted α-ketoamide a superior photoreactive group PAL. Studies with series synthetic mannose-conjugated revealed 2-thienyl substitution decreased the electrophilicity keto and reduced rate photodegradation. Mannose-conjugated thienyl showed greater concanavalin A efficiency than other alkyl or...
Abstract Heparanase is an endo-β-d-glucuronidase that degrades heparan sulfate glycosaminoglycans in the extracellular matrix and basement membrane well known to be involved tumor cell invasion angiogenesis. We have focused on heparanase as a target for antitumor agents, especially antimetastatic agents. (R)-3-hexadecanoyl-5-hydroxymethyltetronic acid (RK-682) was found display inhibitory activity against our screening of natural sources. Because RK-682 has been reported show activities...
Three new 10-membered macrolides, saccharothriolides A–C (<bold>1–3</bold>), were discovered from a rare actinomycete <italic>Saccharothrix</italic> sp. A1506.
Glycoconjugates are an important class of biomolecules that regulate numerous biological events in cells. However, these complex, medium-size molecules metabolically unstable, which hampers detailed investigations their functions as well potential application pharmaceuticals. Here we report sialidase-resistant analogues ganglioside GM3 containing a monofluoromethylene linkage instead the native O-sialoside linkage. Stereoselective synthesis CHF-linked disaccharides and kinetically controlled...
Abstract Microbes have evolved intricate communication systems that enable individual cells of a population to send and receive signals in response changes their immediate environment. In the fission yeast Schizosaccharomyces pombe , oxylipin nitrogen signaling factor (NSF) is part such system, which functions regulate usage different sources. Yet, pathways mechanisms by NSF acts are poorly understood. Here, we show physically interacts with mitochondrial sulfide:quinone oxidoreductase Hmt2...
A CH 2 -linked alpha(2,3)sialylgalactose analogue was efficiently synthesized using an Ireland-Claisen rearrangement, which developed recently by our group for constructing a CF -sialoside. The reaction conditions of the rearrangement were optimized alpha-stereoselective formation On basis observed temperature effects, origin stereoselectivity is discussed. Moreover, reconstruction 2alpha-hydroxyl on galactose unit product achieved means stereoselective dihydroxylation and deoxygenation.
A library of oxygenated natural steroids, including physalins, withanolides, and perulactones, coupled with the synthetic cage-shaped right-side structure type B was constructed. SAR studies for inhibition NF-κB activation showed importance both B-ring partial structure. The 5β,6β-epoxy derivatives physalins withanolides similar profiles appeared to act on signaling via phosphorylation degradation IκBα. In contrast, C5-C6 olefin functionality inhibited nuclear translocation DNA binding...
The unsaturated ester aldehyde, (E)-3-alkoxycarbonyl-5-phenyl-2,4-dienal, was efficiently dimerized by applying the strain-promoted double-click reaction with sym-dibenzo-1,5-cyclooctadiene-3,7-diyne. resulting probe sequentially reacted first one peptide molecule and then a protein or amino groups on surface of live cell through double azaelectrocyclization to achieve highly efficient bioconjugation.
[reaction: see text]. Stereocontrolled synthesis of the ABC ring framework zoanthenol has been achieved. Our studies show that a beta,beta-disubstituted enone can act as good acceptor arylpalladium intermediates in formation congested benzylic quaternary carbon center through an intramoleculer Mizoroki-Heck reaction. The cis B/C system was stereoselectively converted to trans-fused SmI2-promoted deoxygenation alpha-hydroxy ketone.